Rinnai vs Rheem Tankless Water Heater- Which is Better?

Tankless water heaters offer numerous benefits, including cost efficiency, space-saving, and energy efficiency. There are a wide-range of tankless water heater brands on the market and Rinnai and Rheem are two of the most popular ones.

between rinnai vs rheem tankless water heater which is better

Both brands offer a wide variety products to choose from. While Rinnai only offer natural gas and propane tankless heaters, Rheem has gas, propane, and electric tankless heaters.

This article compares Rinnai vs Rheem tankless water heaters side to side by features, pros and cons, and where each brand is most suitable.

About Rinnai

Rinnai was founded in Japan the 1920s. It offers a wide range of products including water heating systems and kitchen appliances. In 2018, the Rinnai American corporation set up a manufacturing facility in Griffin, GA making it the first company to manufacture tankless water heaters in the US. While Rinnai tankless heaters are available at different prices, they are on the high-end range.

Below is a look at the pros and cons of Rinnai tankless water heaters:


  • High quality build
  • Excellent performance and efficiency
  • Advanced additional features
  • Durable


  • Pricey
  • No electric tankless heaters

About Rheem

Rheem has been in the market for over 100 years. The company specializes in hot water heating systems and has a wide range of products including tankless water heaters and even solar water heating systems. Rheem tankless water heaters are among the most affordable on the market.

Below is a look at the pros and cons of Rheem tankless water heaters


  • Affordable
  • Decent quality
  • Gas, propane, and electric models available


  • Lower quality than Rinnai
  • Less sophisticated additional features

Features: Rinnai vs Rheem

35 tankless water heaters


Rheem has over 35 tankless water heaters. While they are easy to install, others require professional plumbing services.

Rheem tankless heaters are either powered by gas, propane, or electricity. Gas heaters have lower operational costs but may be more expensive to install as they require venting. On the other hand, electric tankless water heaters are easy and cheaper to install as they only require a dedicated electrical circuit. The range of Rheem tankless heaters includes both whole-home and point-of-use configurations.

Rinnai has a narrower range of tankless water heaters than Rheem. There are 15 Rinnai tankless water heaters with prices ranging between $600 up to $3000. All the water heaters are either powered by natural gas or propane with none that are electric. The range includes both indoor and outdoor tankless water heaters.

Product quality

Rheem tankless heaters are decent quality products. Some have stainless steel heat exchangers while others are made of copper. Generally, stainless steel is more susceptible to rusting which compromises the units’ durability. Rheem tankless water heater warranties vary from one product to another ranging from 6 months up to lifetime warrantie.

Rinnai products have superior quality. They can last twice as long as other tankless heaters on the market. Part of the reasons why Rinnai tankless heaters last longer is that they are fitted with copper heater exchanges, which are more flexible and make the heaters more durable.

Rinnai is keen to test each product individually before shipping. Therefore, you are unlikely to receive a defective product. The Rinnai residential tankless heaters are backed with a 10-year warranty on the heat exchanger, 1-year labor, and 5-years warranty on parts.

Flow rate and heating power

The Rheem heaters have a heating power capacity ranging between 11,000 BTU up to 190,000 BTU. The flow rate differs from one product to another with smaller ones ranging between 0.9GPM to 3GPM and larger ones ranging between 6GPM and 9GPM.

Comparatively, Rinnai water heaters have a higher flow rate that ranges between 6.3GPM and 11GPM. Similarly, they have a powerful heating capacity with the most sophisticated ones having the capability for up to 4.3M BTU.

Advanced features

Some Rheem tankless heaters have a digital temperature display, some have an LED display, while others do not have a temperature display. Beyond the standard temperature display, some digital displays have additional features such as ON/OFF dial control, temperature settings, and maintenance code display.

A few like the Professional Prestige Series 95 GPM Outdoor Tankless, have a built-in condensate neutralizer. The Professional Classic Series: RTEX-08, RTEX-11, RTEX-13 have self-modulating power control.

The most sophisticated Rheem tankless water heaters have advanced features such as recirculation pump kit compatibility and built-in condensate neutralizer, which reduces installation costs and heating time significantly.

All Rinnai tankless water heaters have a recirculation feature. While some come with the ThermaCirc360 kit already fitted, for others you will need to buy the kit separately. ThermaCirc360 allows you to set recirculation patterns in line with your lifestyle and daily habits.

Some models such as the HE+ Series RL models and SE Series RUCS – Models have a digital display feature while others such as HE Series V-Models do not. Other advanced features found in some Rinnai tankless water heaters include a quick access isolation valve, Wi-Fi connectivity, and voice control

Rinnai vs Rheem tankless water heaters stand out features

Unlike Rheem, Rinnai tankless water heaters are made in the US. These heaters also offer superior efficiency and performance. On the other hand, Rheem has a wide range of tankless water heaters that offer decent efficiency, performance, and output volume at an affordable price.

Our Final Verdict

Instant tankless electric water heater installed on white tile wall

Both Rinnai and Rheem tankless water tanks offer great value for your money. Consider factors such as your hot water demand, budget, and preferred features when choosing a tankless water heater.

Rinnai is the best tankless water heater option if:

  • You have a high hot water demand
  • You want a durable product that will last for many years
  • You are willing to spend a bit more
  • You want a water heater with advanced additional features such as Wi-Fi connectivity and voice control

Rheem is the best tankless water heater option if:

  • You want a wide range of options to choose from
  • Decent quality at an affordable price
  • You need a small tankless water heater

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